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Population Genetics of the Eastern Hellbender (Cryptobranchus alleganiensis alleganiensis) across Multiple Spatial Scales
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Conservation genetics is a powerful tool to assess the population structure of species and provides a framework for informing management of freshwater ecosystems. As lotic habitats become fragmented, the need to assess gene flow for species of conservation management becomes a priority. The eastern hellbender (Cryptobranchus alleganiensis alleganiensis) is a large, fully aquatic paedamorphic salamander. Many populations are experiencing declines throughout their geographic range, yet the genetic ramifications of these declines are currently unknown. To this end, we examined levels of genetic variation and genetic structure at both range-wide and drainage (hierarchical) scales. We collected 1,203 individuals from 77 rivers throughout nine states from June 2007 to August 2011. Levels of genetic diversity were relatively high among all sampling locations. We detected significant genetic structure across populations (Fst values ranged from 0.001 between rivers within a single watershed to 0.218 between states). We identified two genetically differentiated groups at the range-wide scale: 1) the Ohio River drainage and 2) the Tennessee River drainage. An analysis of molecular variance (AMOVA) based on landscape-scale sampling of basins within the Tennessee River drainage revealed the majority of genetic variation (∼94–98%) occurs within rivers. Eastern hellbenders show a strong pattern of isolation by stream distance (IBSD) at the drainage level. Understanding levels of genetic variation and differentiation at multiple spatial and biological scales will enable natural resource managers to make more informed decisions and plan effective conservation strategies for cryptic, lotic species.
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Peer-reviewed Science
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Prevalence of Batrachochytrium dendrobatidis in Eastern Hellbender (Cryptobranchus alleganiensis) Populations in West Virginia, USA
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The eastern hellbender (Cryptobranchus alleganiensis alleganiensis) is a North American salamander species in decline throughout its range. Efforts to identify the causes of decline have included surveillance for the chytrid fungus Batrachochytrium dendrobatidis (Bd), which has been associated with global amphibian population losses. We evaluated the prevalence of Bd in 42 hellbenders at four sites in West Virginia, US, from June to September 2013, using standard swab protocols and real-time PCR. Overall prevalence of Bd was 52% (22/42; 37.7–66.6%; 95% confidence interval). Prevalence was highest in individuals with body weight ≥695 g (χ2=7.2487, df=1, P=0.007), and was higher in montane sampling sites than lowland sites (t=−2.4599, df=44, P=0.02). While increased prevalence in montane sampling sites was expected, increased prevalence in larger hellbenders was unexpected and hypothesized to be associated with greater surface area for infection or prolonged periods of exposure in older, larger hellbenders. Wild hellbenders have not been reported to display clinical disease associated with Bd; however, prevalence in the population is important information for evaluating reservoir status and risk to other species, and as a baseline for investigation in the face of an outbreak of clinical disease.
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Purdue Agriculture Help the Hellbender
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Everyone can do something to Help the Hellbender. On this website, you will find information about the hellbender, as well as household and farm management practices that can help keep our rivers and streams clean. People who fish and kayak can also learn what they should do if they see a hellbender in the wild.
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Training Resources
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Purdue University Help the Hellbender Brochures, Lesson Plans, Videos & Games
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The Hellbender is a giant, aquatic salamander that has experienced severe population declines throughout its range. It is a sensitive species and there are a number of factors contributing to its declines. To help address the varied threats facing the Hellbender, Help the Hellbender has produced several new products focused on educating both stakeholders and the general public on ways that they can help protect hellbenders.
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Training Resources
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Range-wide assessment of grazing and hydrology in bog turtle wetlands
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In December 2018, a meeting of bog turtle experts was hosted in Richmond, VA and experts across the Eastern range of the species identified as a high priority the need to better understand the benefits and potential negative impacts of livestock grazing in bog turtle inhabited wetlands. Hydrologic conditions in bog turtle wetlands emerged as a secondary concern needing more research. Recently, NRCS’ Conservation Effects Assessment Project (CEAP) awarded funds to Dr. Carola Haas leading a team of researchers at Virginia Tech University to conduct an assessment on these two topics (grazing and hydrology).
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WLFW Outcomes: Funded Research
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Researchers study eastern hellbender salamanders parental habits
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Unlike most wildlife species, male hellbenders provide exclusive care for their young for an extended period of seven months.
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Eastern Hellbender News
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Southeastern Hellbender Conservation Initiative
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The Southeastern Hellbender Conservation Initiative (SEHCI), a collaboration between Defenders of Wildlife, NRCS and other conservation partners to support farmers using conservation practices on their lands that help restore hellbender habitat.
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The Effects of Livestock Grazing on the Bog Turtle
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The demise of small-scale dairy farming over the past three decades has led to the pastoral abandonment of the majority of bog turtle habitats in the Northeast. As a consequence, habitats are being degraded by the growth of invasive flora, changes in hydrology, and the loss of turtle microhabitats created by livestock.
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Peer-reviewed Science
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The Last Dragons - Protecting Appalachia's Hellbenders
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An intimate glimpse at North America's Eastern Hellbender, an ancient salamander that lives as much in myth as in reality.... and in many waters, myths are all that remain of these sentinel stream-dwellers. Video by Freshwaters Illustrated.
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The use of nest boxes by the hellbender salamander in Western North Carolina
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The hellbender salamander (Cryptobranchus alleganiensis) is a unique, large-bodied amphibian that serves as an excellent water quality indicator species in Western North Carolina. This animal has suffered substantial population declines over the past four decades throughout its range. Increased stream siltation largely attributed to human development fills the concave undersides of large rocks, consequently destroying hellbender breeding habitat. Habitat degradation has contributed to reductions in North Carolinian populations to such a degree that the species is now considered of Special Concern in the state. In order to restore hellbender population sizes under current land use conditions, researchers have recently begun developing artificial nest boxes that exclude sediment and promote increased reproduction. To identify the short-term efficacy of these shelters as substitutes for natural hellbender habitat in Western North Carolina, I constructed and placed 54 boxes across five river sites throughout the region. Following summer nest box installment, I examined each shelter through the breeding season for hellbender in habitation and to determine the quality of water passing through the structures. Additionally, I created a maximum entropy species distribution model and conducted a spatial connectivity analysis for the hellbenders of Western North Carolina to identify ideal locations for nest boxes installation in the future. Although no hellbenders have yet been detected in the artificial shelters, additional structural improvements and time may reveal nest boxes to be useful conservation tools for this iconic species of Special Concern.
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Artificial Nest Box Research
